using a hose as a siphon then using the hose to fill the aquarium works well although is easier in the country
Water changes
- Thread starter Xingu piranha 2022
- Start date
This is very true, but something that the hobbyist shouldn't get too disheartened about imo. Lowering the nitrate isn't the only important aspect of the water changes we do, there are all kinds of other "immeasureables" in the stale fish tank water too.
So even though your water changes don't directly effect the nitrate level, they will replace/neutralise the other accumulative waste products that have also built up, so you've got yourself a good win from that standpoint.
And also consider that if the vast majority of fish you keep are adults, then slightly elevated nitrate levels are still relatively safe. I no longer believe that having nitrate in your tap water is the end of the world when it comes to keeping mature fish. Breeding? Fry? Juveniles? Maybe not so good long term.
I have always, and will always, do a minimum of 50% water changes every week. Saturdays have been water change day literally for as long as I can remember. Nitrate levels are important as has been discussed, so you very well could need to do larger, more frequent water changes depending on your specific situation based on the bioload of your tank. But I will never do less than once per week even if my nitrate levels are low enough to "not require" it. There are more benefits to fresh water on a very regular basis than just nitrate levels being low.
Generally speaking, I feel the same way. I tend to change more water than 50%, mainly because I can do so without really doing any more work than I would if the change were smaller.
Too many people get caught up with the evil of nitrates; but nitrates are not the only reason for changing water. There are all sorts of biochemical processes constantly occurring in our aquariums, resulting in the build-up of some chemicals and compounds and the depletion of others...and the vast majority of these measurements are impossible, or at least impractical, for the home hobbyist to perform. Nitrate level just happens to be an easy thing for us to measure and control, so we say "change when nitrates reach X level", or Y level, or whatever level we decide we can live with. But when we change the water, we are also reducing all those other unwanted products and by-products of life, as well as replenishing all the trace elements and minerals being utilized by that life.
But nitrates are the bugaboo for most people, so let's consider them alone. As
duanes
and others have explained, most natural environments have nitrate levels close to zero. Since the fish have evolved to be suited to these conditions, common sense tells us that we should try to imitate them. Can we? Not easily, but we do the best we can. Frankly, I don't care how many wanna-be experts or scientists tell me that this or that level of nitrates is or is not dangerous, or will/will not have any deleterious effects on my fish. If the fish don't have high levels of nitrate in nature, I don't want them to have high levels in my tank, so I like changing water. Simple as that, really. I want water changes as close to 100% as possible, although I always leave enough water in the bottom to keep the fish covered throughout the change. 
The howls and wails are almost inevitable now. What? You change almost all your water? At once? Good lord, man, think of the shock those poor fish are being forced to endure? Are you mad????
No...at least, I don't think so.
When you change a lot of water, and do it often, it never degrades to the point where there is a huge difference between the old and the new...there is no shock to the fish. I can't recall any fish that did not look and act at least as good, and usually better, immediately after the change. I recall when I first tried breeding Cherry Shrimp, having read all the warnings about how sensitive they were to changes in water parameters, wondering if they would do well. But, never a problem. I have a turtle who lived with a colony of shrimp for years; the shrimp flourished as long as they had sufficient cover to avoid being eaten...despite several 99% changes per week. No shock, they always lived in water that was almost perfectly stable in parameters, because it was almost always brand new.Fish tend to do very well when you keep their water clean and fresh. They do even better when you never let it get dirty in the first place. That's my goal.
